The compound o-aminophenyl cyclopropyl ketone is a useful intermediate in the manufacture of crop-selective sulfamoyl urea herbicidal agents. It is particularly useful in the manufacture of 1-(o-cyclopropylcarbonyl)-phenylsulfamoyl urea derivatives which are highly potent, yet environmentally benign, cereal crop tolerant herbicides. Methods known to prepare o-aminophenyl cyclopropyl ketone such as those described in U.S. Pat. Nos. 4,160,784 and 5,009,699 use cyclopropylnitrile as starting material. However, cyclopropylnitrile is not commercially nor readily obtainable, whereas 4-chlorobutyronitrile is obtainable commercially. However, there is no effective method available to prepare o-aminophenyl cyclopropyl ketone from its 4-halo acyclic precursor, 1-(o-aminophenyl)-4-halo-1-butanone.
Therefore, it is an object of this invention to provide an effective process for the preparation of o-aminophenyl cyclopropyl ketone via the dehydrohalogenation of 1-(o-aminophenyl)-4-halo-1-butanone.
It is another object of this invention to provide a source of a useful intermediate in the manufacture of herbicidal sulfamoyl urea derivatives.